I don't know if -USEFUA works on the PX-716SA, but I know it's not worth enabling unless you uncheck EAC's caching option - while simultaneously EAC's caching option isn't worth unchecking unless you're employing -USEFUA and you know that it's working. Basically they are a package deal.
If you uncheck EAC's caching option without employing (truly functional) -USEFUA, it will completely defeat the purpose of 'Secure' ripping on any drive which normally does caching. "Track Quality" will always be 100%, because no rereads will ever uncover any problems. Secondary readings will come from the drive cache rather than from the physical disc itself, which means every 'two' readings of the same sector will always match, and no inconsistencies will ever be found.
I would say if you ever see "Track Quality" below 100%, then you know the setup is working properly. Keep that in mind when you fiddle around with these options.
Now C2 is an entirely different beast than AccurateStream. C2 will reread only the problematic areas (or I should say - only the areas your drive perceives as problematic), while AccurateStream rereads everything at least once before it decides if and where there are any problems to warrant further rereads. Fortunately AccurateStream re-re-reads only the problematic areas, but even so, it's a very slow and painful process.
I trust the C2 on my Premium, but only in a -USEFUA scenario. In Test & Copy on a mint condition Michael Jackson boxset disc, I have seen a CRC mismatch with "drive does caching" and C2, which I have never seen with -USEFUA and "drive doesn't do caching". I don't know how or why. I just know that when PlexTools does its ripping, PlexTools employs C2 and -USEFUA simultaneously (at least on the Premium anyway). The problem with PlexTools is the software doesn't have a fallback for when C2 could fail - such as on a copy-protected CD.
I believe the main CD-related claims-to-fame for the PX-716 is that the drive can overread into the lead-in and the lead-out (almost none of the nonPlextors can do this), and it's an acceptably fast drive by AccurateStream standards. I don't know if anyone actually takes the C2 very seriously on the PX-716. I'm not saying they shouldn't - I'm just saying I don't know.
If it's possible for you to do -USEFUA C2 ripping with your PX-716SA the same way I do that with my Premiums, you should test it to be sure. Even if -USEFUA is possible on the PX-716A (ATA model), that doesn't automatically extend to the Serial-ATA model. Tell EAC your drive doesn't do caching, but does do C2. And include -USEFUA in your EAC shortcut before launching EAC. If you ever see any "Track Quality" of under 100%, then the setup is working.
I would say Test & Copy of -USEFUA C2 is more reliable than AccurateStream (with or without Test & Copy) on most discs. It's also much faster, and doesn't put a lot of strain on your drive.